Machinery for extruding metal tubes



H. D.SWIFT AND A. L. SCOTT. MACHINERY FOR EXTRUDING METAL TUBES.

' APPLICATION FILED JULY 18,1919. 1,331,169.

Patented Feb. 17,1920.

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A TTORNEY INVENTORS H. D. SWIFT AND A. L. SCOTT. MACHINERY FUR EXTRUDING METAL TUBES.

APPLICATION FILED JULY 18. I919.

. w... m n1. Vnmibummhw in W W III! [Z I lNl/EfVTORs A T TOR/V5 Y the container and the ram HERBERT D. SWIFT AND ABRAHAM LINCOLN SCOTT,

OF YONKERS, NEW YORK,

ASSIGNOBSTO SWIFT-SCOTT CORPORATION A. CORPORATION OF NEW YORK.

MACHINERY FOR EXTRUDING METAL TUBES.

Specification of Letters Patent.

Patented Feb. 1'7, 1920.

Application filed July 18, 1919. Serial No. 811,708.

To all whom it may concern:

Be it known that we, HERBERT D. Swn r 6 f and ABRAHAM United States, kers county of Westc York, have invented a new and useful I mprovement in Machinery for Extrudmg Metal Tubes, of which the following is a specification.

The invention relates to machmery for extruding metal tubes, particularly non-ferrous tubes. The object is to provide an apparatus having a high rate of output and producing tubing the bore of which is truly concentric to the outer circumference, and further to facilitate withdrawal of the ram from the tube and stump, the removal of the stump from the mandrel, and the insertion of a fresh billet, at the conclusion of the extrusion operation, and at the same time to enable the apparatus to be quickly and readily changed over from one size of bore to another, or the mandrel to be replaced or repaired. The object is also to provide advantageous means for cooling the mandrel, the same means making possible the connection and disconnection of the mandrel unit,

LINCOLN Sc0'rr, citizens of the residin in the cityof Yon; liester, State of New which is rigidly carried by the ram in action.

In addition to the above, it is an object to make the invention applicable to existing rod extrusion presses. These and other objects and features of the invention will become apparent as the specification proceeds.

In the accompanying drawings, forming 2. art hereof:

igure 1 is an axial section of the essentials of the apparatus, with a billet therein, just prior to the commencement of extrusion;

Fi 2 is a view on a smaller scale, showing the billet and mandrel unit in place in about to advance;

Fig. 3 is a view in elevation, showing the extrusion substantially com leted;

Fig. 4 is a further view, s owing the ram retracted, and the mandrel unit, stump and tube out of thecontainer; and

Fig. 5 is an enlarged section showing the expansion nozzle.

v The container 1, die 2, and carriage cylinder 3 With its head 4 may be substantially as in known apparatus. The die may be seated with aclo'se fit in the recess of the carriage head, or in a bushing 5, which can be adjustram in the ct of extruding, of a two-piece unit, the other part of which the tubing minating at the forward ed in all transverse directions by set-screws or purposes of alinement.

The ram 7 has its forward portion turned down to produce a stout elongate c lindrical pm or nose 8 ha a roun ed 'extremlty. The mandrel 9, which forms the interior of the tube, is carried rigidly by the and forms part is a sleeve-base 10 of the same diameter as the ram. Said sleeve-base has an axial socket 11 corresponding to the pin 8, the pin and socket being accurately formed and ground to produce a tight-fitting joint capable of separation, the length of the joint insuring rigidity. The detachable plug is thus held exactly in alinement with the center line of the ram, which is solidly and accurately supported and guided, and when the machine is once set up will continue to produce a consistently concentric hole in without further adjustment.

e mandrel is connected with its sleevebase by a. screw joint consisting of a stout threaded stem 12 on the rear end of the mandrel and a corresponding threaded socket 13 in the forward end of the sleeve-base. The basal region of the mandrel is flared as indicated at 14, for the double purpose of making it easy to release the mandrel from and of affording a wide flat shoulder 15, which by bearing against the square end of the sleeve-base prevents all possrbllity of deflection of the mandrel relatively to this part, which in its turn, as already explained, is held in rigid center alinement with the ram.

A longitudinal duct 16 is formed in the forward part of the ram and its pin 8, terend of the latter, and havlng a lateral entrance duct 17 to which is connected a flexible external conduit 18, whereby the duct is su plied with a current of air under pressure, i rom a suitable source not necessary to illustrate. The mandrel 9 also has an axial duct 19, extending through from the rear face of the screw stem 12 to the front extremity; and these duct sections 16 and 19 are in communication by an expansion nozzle or valve 20 secured in an opening in the forward portion of the sleeve-base 10, between the pin socket 11 and the screw-connection socket 13. A vent is thus provided for escape of air when the nose of the ram is pushed into its socket in the sleeve-base, and conversely for allowing entrance of air to the ground oint when the parts are pulled apart. The compressed air supplied through the sectional.

duct during extrusion minimizes expansion and contraction in the mandrel and preserves its temper, so that it will not. fail when subjected to the heavy stresses under the high temperature present. The same air discharged at the end of the mandrel cools the tubeand keeps it from'remaming plastic. The cooling effect is obtained both by convection and by the expansion of the air into the mandrel, through the nozzle 20 adjacent its base. The cooling duct passing through the joints also tends -to keep the members thereof from loosening under the high temperatures.

In operation, the die having been set up accurately, the billet a, which is cast with a tapered hole through the center of it, is

put into a mufiie and heated to a. cherry red.

" The billet is then taken from the mufile,

and the mandrel unit, consisting of the mandrel and sleeve-base, disconnected from the ram, is inserted into the billet. Next the mandrel unit and billet are pushed into place in the container. This is the condition illustrated in Fig. 2. The ram is caused to advance and its pin nose 8 enters the socket 11 of the sleeve-base, and the air which would otherwise be trapped and act as a cushion is expelled through the vent as .heretofore explained. Themandrel unit is now practically integral with the ram, and further forward movement causes the metal of the billet to flow and to be squirted through the die and around the advancing mandrel in the manner well understood.

'During this operation the sleeve-base acts as a dummy-block; and throughout the extrusion a flow of air is maintained through the ram and mandrel unit and expanded into the mandrel, to the ends already described. When as much of the billet as is to be extruded has been forced out of the die, the ram is withdrawn and the ground joint separates, leaving the mandrel unit in the stump b and tube 0, as seen in Fig. 4:. The carriage cylinder 3 is also withdrawn, and the mandrel unit and stumptare displaced out of the front of the container. The mandrel unit can now be separated from the stump and tube. In case the mandrel should stick, it is released from the sleeve-base by unscrewing the screw joint, after which it can be more easily freed from the stump. The separability of the mandrel and sleeve-base also permits of the mandrel being exchanged for others of different sizes, in .order that tubes may be manufactured having bores of different size and remaining as a common dummyblock, to which any size of mandrel may be secured. Removal of the mandrel is of further advantage when it becomes necessary to grind the surface of the plug or to make other repairs.

What is claimed as new is:

1. In an apparatus for extruding tubes having a billet-container and a die, the com bination of a ram having a projecting nose in the form of an elongate pin, and a separable mandrel unit comprising a mandrel, and a dummy-block sleeve-base having a socket adapted accurately to fit the pin, and a detachable screw connection between the butt of the mandrel and the sleeve-base.

2. In an apparatus for extruding tubes having a billet-container and a-die, the com bination of a ram having a projecting nose in the form of an elongate pin, and a separable mandrel unit comprising a mandrel, and a dummy-block sleeve-base having a socket adapted accurately to fit the pin, the nose of the ram and the mandrel unit having a vent therethrough permitting connection and disconnection, and means for sup plying air for cooling through said vent.

3. In tube extrusion apparatus, a mandrel having a longitudinal air-duct, and an expansion nozzle adjacent the base of the mandrel.

4:. In an apparatus for extruding tubes having a billet-container and a die, the combination of a ram having a projecting nose in the form of an elongate pin, and a separable mandrel unit comprising a mandrel, and a dummy-block sleeve-base having a socket adapted accurately to fit the pin, the nose of the ram and the mandrel unit having a vent therethrough permitting connection and disconnection, means for supplying air for cooling through said vent, and an expansion nozzle in the separable part adjacent the base of the mandrel.

5. In an apparatus for extruding tubes havmg a billet-container and a die, the comb1nat1on of a ram having a projecting nose in the form of an elongate pin, and a Separable mandrel unit comprising a mandrel, and a dummy-block sleeve-base having a socket adapted accurately to fit the pin, and a. detachable screw connection between the butt of the mandrel and the sleeve-base, said ram pm, sleeve-base and mandrel containing portions of a longitudinal cooling passage.

6. In tube-extrusion apparatus, the combinatlon of a ram, a separable mandrel unit, sa1d ram and unit being formed with the members of a ground-fitting joint, and means for cooling said joint.

7. In tube-extrusion apparatus, the combination of a ram, a separable two-piece unit comprising a base the diameter of the ram and a mandrel, said ram and base having the members of a ground-fitting joint, and the base and mandrel the members of a screw parts being further provided with a cooling duct passing through said joints. I

8. In tube-extrusion apparatus having a billet-container and a die, the combination of a ram and a separable mandrel unit having a base fitting the container, said ram and mandrel unit being formed With the members of a cylindrical elongate ground pin and socket joint.

9. In tube-extrusion apparatus having a billet-container and a die, the combination of a ram and a separable mandrel unit having a base fittin the container, said ram and mandrel unit being formed With the members of a cylindrical elongate ground pin and socket joint, and means for venting said 'oint.

J 10. In tube-extrusion apparatus having a billet-container and a die, the combination of a ram and a separable mandrel unit havjoint, and the ing a base fitting the container, said ram and mandrel unit being formed with the members of a cylindrical elongate ground-pin and socket joint, and being further provided with an air duct traversing said joint and discharging at the end of the mandrel, and means for supplying air through the duct.

In an apparatus for extruding tubes having a bille -container and a die, the combination of a ram having a projecting nose in the form of an elongate pin, and a separable mandrel unit comprising a mandrel, and a dummy-block sleeve-base having a socket adapted accurately to fit the pin, and a detachable screw connection betyveen the butt of the mandrel and the sleeve-base, the butt of the mandrel being flared and bearing with a wide shoulder against the sleeve-base.

HERBERT D. SWIFT. A. LINCOLN SCOTT. 

